release: bump 0.8.8 -> 0.8.9 (#285)

Maintenance release — supply-chain and CI housekeeping only. No library code or
public API changes.

### Security
- Triaged the pyo3 advisories RUSTSEC-2026-0176 / RUSTSEC-2026-0177 as not
  affecting Wickra (vulnerable APIs unreachable from the binding; fix blocked
  upstream by rust-numpy pinning pyo3 `^0.28`). Recorded in `deny.toml` and
  `osv-scanner.toml`.

### Changed
- Java binding: `central-publishing-maven-plugin` 0.5.0 → 0.10.0.
- CI GitHub Actions bumped to latest (checkout, setup-go, setup-java,
  codeql-action, taiki-e/install-action).
- Added a Maven ecosystem to Dependabot.

Version bumped across all manifests/lockfiles via `bump_version.py`; Cargo.lock
refreshed. CHANGELOG `[0.8.9]` filled. Tag/publish to follow on explicit GO.

bindings/java/README.md

@@ -30,14 +30,14 @@ Maven:
 <dependency>
   <groupId>org.wickra</groupId>
   <artifactId>wickra</artifactId>
-  <version>0.8.8</version>
+  <version>0.8.9</version>
 </dependency>
 ```
 
 Gradle:
 
 ```kotlin
-implementation("org.wickra:wickra:0.8.8")
+implementation("org.wickra:wickra:0.8.9")
 ```
 
 The native library ships prebuilt per platform (Linux, macOS, Windows — x64 and

bindings/java/pom.xml

@@ -6,7 +6,7 @@
 
   <groupId>org.wickra</groupId>
   <artifactId>wickra</artifactId>
-  <version>0.8.8</version>
+  <version>0.8.9</version>
   <packaging>jar</packaging>
 
   <name>Wickra</name>